ALSA: hda: Use quirk mask for Dell Inspiron Mini9/Vostro A90 using ALC268

BugLink: https://bugs.launchpad.net/bugs/368629

We should use a quirk mask for these Dell Inspiron Mini9s and Vostro
A90s, as the model=dell quirk appears to enable audio on them.

Signed-off-by: Daniel T Chen <crimsun@ubuntu.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>